I'd say that I've had a lot of great experiences at the theater. Personally, I have rarely had a bad experience because even for films that weren't that great, I shared them with great family and friends. More ot your point, the best cinematic experience I've ever had was watching a Roger Waters: The Wall Live. A visual experience for listening to the wall album by Pink Floyd. Simply beautiful!
RE: What is the best cinematic experience you've ever had and why?